1-Phenyl-4-(2-tetralyl)butane and 1-phenyl-4-(1-tetralyl)butane, both known as PTB, are known compounds which are obtained by treating 1,2,3,4-tetrahydronaphthalene (tetralin) with a strong acid catalyst: ##STR1## This reaction is discussed in Ber. 57B, 1990 (1924) and in U.S. Pat. No. 3,336,407 where it is pointed out that not only PTB, but other reaction products as well, such as sym-octahydroanthracene (OHA) and sym-octahydrophenanthrene (OHP) are formed. OHA and OHP are known to be plasticizers for polystyrene (U.S. Pat. Nos. 2,289,743 and 2,454,851) but, because of their high volatility they would be of little value for most plasticizer applications in polyvinylchloride (PVC) resins due to unacceptably low levels of permanence resulting from evaporative losses.
Alkylbiphenyls (U.S. Pat. No. 2,172,391), cyclohexylbiphenyls (U.S. Pat. No. 4,167,504) and partially hydrogenated terphenyls (U.S. Pat. Nos. 2,155,524 and 2,925,398) represent specific hydrocarbon types which have been said to be useful as vinyl plasticizers. These all have molecular weights in the approximate range of 180 to 240, again imparting to them a volatility too high for acceptable permanence in most PVC formulations. Although chemically quite distinct from the materials of the present invention, these materials are cited as hydrocarbon plasticizers of known compatibility, volatility and plasticization efficiency for the purpose of comparison.